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Biomedical subjects

F A Hoffer

Publications and source records attributed to F A Hoffer.

At least 55 records · Page 3Linked to original sources
PubMed1996

Percutaneous biopsy for prognostic testing of neuroblastoma.

PURPOSE: To determine whether percutaneous biopsy can provide the diagnostic and prognostic information necessary to treat children with advanced neuroblastoma. MATERIALS AND METHODS: From 1991 through 1995, 21 percutaneous biopsies were performed in 20 children with advanced neuroblastoma by using 15- or 16-gauge core biopsy needles. An average of six samples were obtained. Since September 1994, fresh tissue was sent to the reference laboratory, where touch preparations were prepared for N-myc evaluation. RESULTS: Histologic confirmation and prognostic information (Shimada classification) were obtained in all cases. Genetic prognostic information was obtained in 19 patients (95%), DNA index (ploidy) in 18 (90%), N-myc gene expression in 14 (70%), and cytogenetic analysis in 10 (50%). N-myc and ploidy determinations were successful in all five biopsy specimens obtained since September 1994. CONCLUSION: Percutaneous biopsy of advanced neuroblastoma is a feasible alternative to open biopsy.

Adolescent↗
PubMed1993

Duplex Doppler examination of renal allografts in children: correlation between renal blood flow and clinical findings.

We reviewed the diastolic blood flow (DBF), pulsatility index (PI), and resistive index (RI) in 211 duplex Doppler ultrasound examinations of 63 pediatric renal transplant recipients. We correlated our findings with the clinical diagnosis, independently determined at the time of ultrasound examination. DBF, evaluated in 202 examinations, was found to be decreased, absent, or reversed in acute rejection (kappa = 0.4, p < 0.01) and acute tubular necrosis (ATN) (kappa = 0.3, p < 0.01). The PI and RI were evaluated in 87 and 78 ultrasound examinations respectively. The range of normal PI and RI values in recipients between six and 18 years of age were similar to those reported in adults. However, normal PI and RI values were somewhat higher in recipients less than six years of age who had received adult donor allografts. Overall, the PI was greater than 1.5 in acute rejection (kappa = 0.3, p < 0.05) and ATN (kappa = 0.3, p < 0.01), but not in chronic rejection (kappa < 0, p = NS). The RI was greater than 0.7 in chronic rejection (kappa = 0.3, p < 0.05) and ATN (kappa = 0.3, p < 0.05), but not in acute rejection (kappa = 0.03, p = NS). We conclude that the PI and RI vary in pediatric recipients of renal allografts and are not associated with a specific clinical diagnosis.

Adolescent↗
PubMed1993

Joint effusion in children with an irritable hip: US diagnosis and aspiration.

Ninety-six children with an irritable hip possibly representing septic arthritis underwent clinical and laboratory evaluation, radiography, and ultrasonography (US). Forty had normal US scans; none were later shown to have septic arthritis, although three had osteomyelitis. Fifty-six children had effusion at US. Thirty-one of these underwent US-guided aspiration, two unsuccessfully. On the basis of results of aspirate analysis, 15 of these 31 patients underwent surgical drainage, and septic arthritis was diagnosed in all 15. The mean peripheral white blood cell (WBC) count was not significantly higher in patients with septic arthritis (n = 21) than in patients with toxic synovitis (n = 24) (P = .44). However, the erythrocyte sedimentation rate and synovial fluid WBC count were significantly greater in those with septic arthritis than in those with toxic synovitis (P = .002 and P < .0001, respectively). Clinical evaluation, radiographs, and sonograms together determined the need for US-guided aspiration. US-guided aspiration allowed selection of only those with septic arthritis for operative drainage and shortened that procedure. Negative sonograms allow exclusion of septic arthritis but not osteomyelitis.

Adolescent↗
PubMed1993

Wilms tumor and nephroblastomatosis: imaging characteristics at gadolinium-enhanced MR imaging.

Twelve children with Wilms tumors were prospectively evaluated with 1.5-T magnetic resonance (MR) imaging. Spin-echo images were obtained before and after administration of gadopentetate dimeglumine. Nine of the 12 children had histologically proved nephroblastomatosis or nephrogenic rests involving a total of 14 kidneys. MR imaging depicted involvement in eight of these kidneys, including five of five kidneys with lesions contralateral to the primary Wilms tumor. Overall sensitivity of detection of nephrogenic rests was 43% on nonenhanced images and 58% when gadolinium-enhanced images were added. Nephrogenic rests admixed with Wilms tumors less than 4 mm in diameter were not depicted at MR imaging. On gadolinium-enhanced T1-weighted images, Wilms tumors and hyperplastic were hypointense to normal renal tissue. On T2-weighted images, Wilms tumors and hyperplastic nephrogenic rests were iso- or slightly hyperintense to renal cortex, while sclerotic nephrogenic rests were hypointense to renal cortex. On all images, including gadolinium-enhanced T1-weighted images, the signal intensity of Wilms tumors was inhomogeneous, while the signal intensity of nephrogenic rests was homogeneous.

Child↗
PubMed1993

Devices for transcatheter closure of intracardiac defects.

Transcatheter closure of intracardiac defects is an investigational procedure that is in use at a number of centers in North America and Europe. A radiologist should be able to recognize these devices on a chest radiograph, understand their actual physical appearance, and be able to recognize their expected location. This essay summarizes the indications for, technical aspects of, and radiologic appearance of these devices.

Cardiac Catheterization↗
PubMed1992

Osteomyelitis in children: gadolinium-enhanced MR imaging.

Fifteen pediatric patients with biopsy- or culture-proved nonspinal osteomyelitis were studied with magnetic resonance (MR) imaging. Osteomyelitis was acute in seven patients, subacute in three, and chronic in five. Four patients had subperiosteal abscesses, one had a large associated soft-tissue abscess, and one had an intraosseous (Brodie) abscess. Areas of active inflammation had decreased marrow signal intensity on T1-weighted images, increased signal intensity on T2-weighted images, and enhancement on T1-weighted images obtained after gadopentetate dimeglumine administration (n = 10). Abscesses were rim enhancing (n = 3) or not (n = 2) with gadolinium-enhanced MR imaging. Nonenhancing areas presumably represented necrotic material. Gadolinium-enhanced MR imaging assisted in definition of the presence and extent of nonvascularized fluid collections within the bone and/or adjacent soft tissues and the extent of bone involvement in patients with chronic osteomyelitis. It also helped guide surgical debridement of intraosseous disease (n = 7) and open or percutaneous drainage of subperiosteal or soft-tissue fluid collections (n = 5).

Abscess↗
PubMed1992

Cartilaginous epiphysis and growth plate: normal and abnormal MR imaging findings.

The cartilaginous structures at the ends of growing bones constitute the "growth mechanism." These structures are not visible on radiographs, but they can be seen with MR imaging. Improved definition of cartilaginous abnormalities by MR imaging may permit earlier detection and treatment of these disorders and thus prevent bone deformity. This pictorial essay contains examples of normal and abnormal growth cartilage as seen with MR imaging. The indications for MR imaging in the evaluation of certain growth disorders are discussed, and the usefulness of MR imaging in certain clinical situations in which the role of this technique is still evolving is illustrated.

Bone Diseases↗
PubMed1991

Diagnostic relevance of clonal cytogenetic aberrations in malignant soft-tissue tumors.

BACKGROUND: Malignant soft-tissue tumors often present substantial diagnostic challenges. Chromosome aberrations that might be diagnostic have been identified in some types of soft-tissue tumors, but the overall frequency and diagnostic relevance of these aberrations have not been established. METHODS: We attempted to determine the karyotypes of a series of 62 consecutive, unselected malignant spindle-cell or small round-cell soft-tissue tumors (from 46 adults and 16 children) after direct harvesting of cells or short-term culture. All tumors were examined independently by immunohistochemical staining in addition to routine light-microscopical evaluation, and all but two tumors were examined by electron microscopy. RESULTS: Metaphases were obtained from 61 of the 62 tumors, and clonal chromosome aberrations were identified in 55 (89 percent). In the six tumors that yielded metaphases but lacked apparent clonal aberrations, the normal metaphases were found to originate from non-neoplastic stromal elements within the tumor specimens. Thus, all tumors in which karyotyping was successful contained clonal chromosome aberrations. Forty of 62 tumors (65 percent) contained clonal chromosome aberrations that either suggested or confirmed a specific diagnosis; in 15 of these tumors (24 percent of all tumors), the aberrations were important in establishing the final diagnosis. Cytogenetic analyses were particularly informative about small round-cell tumors from children: 8 of 14 round-cell tumors contained diagnostically important chromosome aberrations. Using the combined approaches of light and electron microscopy, immunohistochemistry, and cytogenetics, we established an unambiguous diagnosis for 60 of 62 tumors. CONCLUSIONS: Cytogenetic analyses reveal clonal chromosome aberrations in virtually all malignant soft-tissue tumors. These clonal chromosome aberrations, particularly in small round-cell tumors in children, often have diagnostic relevance.

Adult↗
PubMed1991

1D spectroscopic imaging with rf echo planar (SIRFEN) methods.

A recently developed rf echo planar imaging method has been modified to rapidly generate spectroscopic information along one in-plane axis and spatial information along the other. The method allows the production of one-dimensional chemical shift images (1D CSIs) in acquisition times of 18 sec or less. A specific phase-encode-reordering algorithm provides convenient manipulation of T2 weighting, yielding partial suppression of short T2 species like muscle water. The method is demonstrated in phantoms and in vivo with 1D CSIs of human brain and limbs. Abnormal fat distribution is demonstrated in the calf of a patient with aggressive fibromatosis. The advantages of short acquisition times obtainable with SIRFEN are offset by limited spectral resolution, suggesting that primary applications will be confined to rapid spatial mapping of major spectral components.

Algorithms↗
PubMed1991

Epiphyseal marrow in infancy: MR imaging.

Hypointense epiphyseal marrow on T1-weighted magnetic resonance images often suggests disease. To determine whether hypointense marrow sometimes represents normal red marrow in a recently ossified epiphyseal center, the authors studied 38 infants without known marrow disease. Patients with hypointense epiphyseal marrow on T1-weighted images were younger (3.9 months +/- 3.2) than those with hyperintense marrow (9.6 months +/- 3.9) (P less than .001). T1-weighted imaging and histologic correlation were also performed in animals. The signal was hypointense and the marrow was red in the epiphyseal centers of all newborn animals, while all 6-week-old animals had hyperintense signal and yellow marrow. The authors conclude that hypointense marrow on T1-weighted images represents normal red marrow in a recently formed ossification center in newborn rabbits and lambs, and the same is probably true in humans. Epiphyseal marrow becomes hyperintense within a few months of development of the secondary center of ossification.

Animals↗
PubMed1991

Multiple collaterals to hepatic infantile hemangioendotheliomas and arteriovenous malformations: effect on embolization.

Hemangioendotheliomas and arteriovenous malformations (AVMs) of the liver often cause congestive heart failure in babies, but embolization of the hepatic artery is not always effective. Six newborns and infants (four with hemangioendotheliomas and two with AVMs) underwent abdominal aortography, hepatomesenteric arteriography, and angiography of arterial and portal collateral vessels prior to embolization of the hepatic artery for heart failure (n = 5) and portal hypertension (n = 1). In addition, extrahepatic arteries were embolized in one patient and a portal vein branch in another. Extrahepatic arterial collaterals from the superior mesenteric, intercostal, phrenic, and adrenal arteries were seen in five patients; portal vein connections, in two patients. Embolization was therapeutically most effective in the baby with the least collateral supply and in the two patients in whom arterial collaterals or portal venous connections were embolized. Angiographic documentation and possibly embolization of collateral flow is required to improve treatment planning and success in these severely ill patients.

Angiography↗
PubMed1990

Urinoma drainage for neonatal respiratory insufficiency.

This report describes two newborn males with posterior urethral valves, perirenal urinomas and respiratory distress. A 400 cc urinoma was drained percutaneously with resolution of respiratory symptoms in the first case. A 120 cc urinoma was drained in the second case but the infant died of pulmonary hypoplasia at 22 h of age. This report emphasizes the importance of aspirating or draining the urinoma in an attempt to treat the newborn's respiratory insufficiency.

Drainage↗
PubMed1990

Pitfalls in pediatric urinary sonography.

Our review of pediatric urinary tract ultrasonograms over a period of two and one-half years resulted in a catalog of pitfalls. Cases included normal scans mistaken for abnormal and vice versa. These erroneous diagnoses stemmed from the inappropriate selection of the primary imaging test, improper timing of the ultrasonogram, errors of commission or omission in performance of the scans, and improper interpretation of the findings. For ease of reference, the pitfalls are grouped under bladder, ureters, and kidney with emphasis on the first two which are common sources of error.

Child↗
PubMed1990

Posttraumatic growth-plate abnormalities: MR imaging of bony-bridge formation in rabbits.

The formation of a bony bridge across the growth plate was studied with magnetic resonance (MR) imaging, tomography, and histologic examination in 12 rabbits. Histologic studies performed 0-8 weeks after the creation of a defect in the physis demonstrated transphyseal bone formation with no evidence of cartilage repair. Gadolinium enhancement indicated the development of vascularity through the plate, which preceded the formation of a bony bridge. Enhancement was faint at 4 days after surgery, was inhomogeneous at 1 week, was maximal at 2 weeks, and decreased at 3 weeks and beyond as the lesion was replaced by bone. A dark rim representing bone deposition at the periphery of the lesion was seen at 2 weeks. At 4 weeks and beyond, the bridge was seen as a dark band of dense bone or as a wider area that was isointense with adjacent fatty marrow. Abnormality in the cartilage and development of transphyseal vascularity, which precede the formation of a bony bridge after trauma, can be detected with MR imaging.

Animals↗